Small-sized to mid-sized display units used for portable devices such as smartphones and tablet terminals have been requested to have a high-definition display performance with low power consumption and to have a thin and light-weight design property. As the display units that meet these requests, a display unit with use of an organic light-emitting device (OLED), i.e., an organic EL display unit has attracted attentions. The organic EL display unit is a self-luminous display unit, and thus has a wide viewing angle and does not necessitate a backlight. Therefore, the organic EL display unit has features such as low power consumption, responsiveness, and decrease in thickness of the display unit itself, compared with a display unit with use of liquid crystal.
Further, the small-sized to mid-sized display units have been requested to enlarge an effective display region as a measure to seek the design property, and thus have been requested to narrow the width of a so-called bezel portion (frame portion) on the periphery of the display region (i.e., narrow bezel has been requested).
The narrow bezel has also been requested in large-sized display units. For the large-sized display units, developments of ultra-multi-pixel displays such as 4K2K displays and 8K4K displays have been under way. Ultra-large-sized displays having a size of 100 inches or more, for example, have been increasingly demanded, because pixel roughness is less likely to be noticeable even when the display region is increased in size. Such ultra-large-sized displays may be achieved by manufacturing an ultra-large-sized display panel through combination of a plurality of display panels in terms of the number and the yield of the ultra-large-sized displays, and the cost. In this case, reduction in the bezel region of the display panels to be combined is requested.
In contrast, the organic EL display unit includes, as a light-emitting device, an organic EL device made of a material containing an organic material. In the organic EL device, layers containing an organic material (organic layers) such as a hole injection layer, a light-emitting layer, and an electron injection layer are stacked between an anode and a cathode. The organic layers react easily with moisture and oxygen in the atmosphere, and are deteriorated. The deteriorated organic layer decreases performances as the light-emitting device, such as decrease in light emission luminance and unstable light emission.
PTL 1 and PTL 2 disclose, as methods for preventing entering of, for example, moisture and oxygen into the organic layer, an organic EL unit in which a region from an emission region to a side surface thereof is covered with a gas barrier layer (or a barrier film) made of an inorganic material.